An ERF Gene DcERF3 of Dendrobium catenatum Improves Salt Tolerance in Arabidopsis

The ethylene-responsive transcription factors (ERFs) perform pivotal regulatory functions in plant growth, development, and stress responses. Nonetheless, there is limited research on the functional characterization of ERFs in the medicinal orchid, Dendrobium catenatum. Here, we identified a salt-induced ERF gene DcERF3 from a D. catenatum cultivar Tiepi. DcERF3 comprises 186 amino acids and has a confirmed molecular weight of 21 kDa. It possesses a conserved AP2/ERF domain and displays a strong affiliation with the evolutionary lineage of other characterized ERFs. Analysis of expression patterns indicated that DcERF3 exhibits predominant expression in stems and roots, with considerably higher levels than in other tissues, and it demonstrated significant upregulation in response to treatments involving salt, ETH, PEG, and SA. The DcERF3-YFP protein localizes to the nucleus, and DcERF3 displays distinct transcriptional activation characteristics. Overexpressing DcERF3 led to an increased lateral root formation and enhanced tolerance to salt stress in Arabidopsis. Furthermore, the activities of antioxidant enzymes, along with the stress-responsive genes, were significantly induced in transgenic plants when subjected to salt stress. This study aims to investigate the function and role of DcERF3 in D. catenatum to establish a foundation for examining its involvement in lateral root formation and response to salt stress.